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Laboratory ManuaL
I n t r o d u c t o r y
GeoloGy
Bradley Deline, PhD
Randa Harris, MS
Karen Tefend, PhD
LABORATORY MANUAL
I N T R O D U C T O R Y
GEOLOGY
Bradley Deline, PhD
Randa Harris, MS
Dahlonega, GA
Karen Tefend, PhD
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Table
of
C onTenTs
CHAPTER 1: INTRODUCTION TO PHYSICAL GEOLOGY
Bradley Deline
1
CHAPTER 2: EARTH’S INTERIOR
22
CHAPTER 3: TOPOGRAPHIC MAPS
41
CHAPTER 4: PLATE TECTONICS
65
CHAPTER 5: WATER
90
Randa Harris and Bradley Deline
Karen Tefend and Bradley Deline
Bradley Deline
Randa Harris
CHAPTER 6: CLIMATE CHANGE
121
CHAPTER 7: MATTER AND MINERALS
140
CHAPTER 8: IGNEOUS ROCKS
177
CHAPTER 9: VOLCANOES
205
CHAPTER 10: SEDIMENTARY ROCKS
227
CHAPTER 11: METAMORPHIC ROCKS
261
CHAPTER 12: CRUSTAL DEFORMATION
286
CHAPTER 13: EARTHQUAKES
313
CHAPTER 14: PHYSIOGRAPHIC PROVINCES
334
Bradley Deline
Randa Harris
Karen Tefend
Karen Tefend
Bradley Deline
Karen Tefend
Randa Harris and Bradley Deline
Randa Harris
Bradley Deline
4
Plate Tectonics
Bradley Deline
4.1 INTRODUCTION
n ha ter one, e re ie ed the s ienti method and the e a t meanin of a
theory, which is a well-supported explanation for a natural phenomenon that still
cannot be completely proven. A Grand Unifying Theory is a set of ideas that
is entra and essentia to a e d of study su h as the theory of ra ity in hysi s
or the theory of evolution in biology. The Grand Unifying Theory of geology is the
theory of Plate Tectonics, hi h de nes the outer ortion of the earth as a rittle outer layer that is broken into moving pieces called tectonic plates. This theory is supported by many lines of evidence including the shape of the continents,
the distribution of fossils and rocks, the distribution of environmental indicators,
as well as the location of mountains, volcanoes, trenches, and earthquakes. The
movement of plates can be observed on human timescales and easily measured
using GPS satellites.
Plate tectonics is integral to the study of geology because it aids in reconstructin earth s history his theory he s to e ain ho the rst ontinents ere ui t,
how oceans formed, and even helps inform hypotheses for the origin of life. The
theory also helps explain the geographic distribution of geologic features such as
mountains, volcanoes, rift valleys, and trenches. Finally, it helps us assess the potential risks of geologic catastrophes such as earthquakes and volcanoes across
the earth. The power of this theory lies in its ability to create testable hypotheses
regarding Earth’s history as well as predictions regarding its future.
4.1.1 Learning Outcomes
After completing this chapter, you should be able to:
• Explain several lines of evidence supporting the movement of tectonic plates
• Accurately describe the movement of tectonic plates through time
• Describe the progression of a Hawaiian Island and how it relates to the
Theory of Plate Tectonics
a e
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
• Describe the properties of tectonics plates and how that relates to the
proposed mechanisms driving plate tectonics
•
e a e to des ri e and identify the features that o ur at di erent
boundaries
ate
4.1.2 Key Terms
• Continental Crust
• Slab Pull
• Convergent Boundary
• Slab Suction
• Divergent Boundary
• Subduction
• Grand Unifying Theory
• Tectonic plates
• Hot Spot
• Theory of Plate Tectonics
• Oceanic Crust
• Transform Boundary
•
•
id e ush
adati
enio
one
4.2 EVIDENCE OF THE MOVEMENT OF CONTINENTS
The idea that the continents appear to have been joined based on their shapes is
not ne , in fa t this idea rst a eared in the ritin s of ir ran is a on in
The resulting hypothesis from this observation is rather straightforward: the shapes
of the ontinents t to ether e ause they ere on e onne ted and ha e sin e roken apart and moved. This hypothesis is discussing a historical event in the past and
cannot be directly tested without a time machine. Therefore, geoscientists reframed
the hypothesis by assuming the continents used to be connected and asking what
other atterns e ou d e e t to nd his is e a t y ho turn of the entury earth
s ientists su h as fred e ener addressed this im ortant s ienti
uestion
e ener om i ed ro ty es, fossi o urren es, and en ironmenta indi ators
ithin the ro re ord on di erent ontinents fo usin on fri a and outh merica) that appear to have been joined in the past and found remarkable similarities.
ther s ientists fo o ed suit and the s ienti
ommunity as a e to om i e
an extensive dataset that indicated that the continents were linked in the past in
a su er ontinent a ed an aea oined y fred e ener and ha e shifted to
their current position over time. Dating these rocks using the methods discussed
in chapter one allowed the scientists to better understand the rate of motion, which
has assisted in trying to determine the mechanisms that drive plate tectonics.
4.3 LAB EXERCISE
his a
i use t o di erent ays to in ut your ans ers
ost of the uestions will be multiple choice and submitted online as you have in previous labs.
Other questions will give you a blank box to input your answer as text. Your professor will manually grade this text, such that the format is not as important as your
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INTRODUCTORY GEOLOGY
PL ATE TECTONICS
answer. This format allows you the opportunity to show your work using simple
symbols and allows the instructor to better see your thought process. Also note,
that for many of these questions there is not a single correct answer and seeing
your thought process and understanding the material is more important than your
answer. Therefore, it is important to show your work.
In addition, several of the exercises that follow use Google Earth. For each
uestion or set of uestions aste the o ation that is i en into the sear h o
amine ea h o ation at mu ti e eye a titudes and di erin amounts of ti t or
any measurements use the ruler tool, this can be accessed by clicking on the ruler
icon above the image.
Part A – Plate Motion and Evidence
As was mentioned above one of the most striking things about the geography
of the ontinents today is ho they a ear to t to ether i e u e ie es he
reason for this is clear: they once were connected in the past and have since separated shifting into their current positions. Open Google Earth and zoom out to an
eye a titude of
mi es
amine the oast ines of eastern outh meri a and
estern fri a and noti e ho
e they mat h in sha e
here are s ienti a y im ortant ro de osits in southern ra i , outh
America and Angola, Africa that show the northernmost glacial deposits on the
ancient continent of Pangaea, which indicates these two areas were once connected. Based on the shape of the two coastlines, give the present day latitude and
longitude of two sites along the coast of these countries that used to be connected
hen the t o ontinents ere oined as a art of an aea note there are mu ti e
correct answers):
1.
ra i
2.
n oa
3.
atitude and on itude
atitude and on itude
easure in entimeters the distan e
a en th et een the t o oints you
recorded in the previous question. Given that this portion of Pangaea broke
apart 200,000,000 years ago, calculate how fast South America and Africa are
se aratin in m year
int
eed
istan e ime
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INTRODUCTORY GEOLOGY
4.
PL ATE TECTONICS
hen i the ne t su er ontinent form
amine the estern oast of outh
meri a, the astern oast of sia, and the a i
ean f outh meri a and
Africa are separating and the Atlantic Ocean is growing, then the opposite must
e o urrin on the other side of the earth the meri as are ettin
oser to
sia and the a i
ean is shrin in
o far a art are orth meri a and
ain and sia in m measure the distan e a ross the a i at
de rees
north latitude- basically measure between Northern California and North
Korea)? Take that distance and divide it by the speed you calculated in question
3 to estimate when the next supercontinent will form. Show your work!
se the i ures
and
to ans er uestions
Figure 4.1
Figure 4.2
Figures 4.1 and 4.2 | The distribution across Australia and Antartica (Figure 4.1) of the fossil snake
Patagoniophis (Figure 4.2). Obviously, this small snake was unable to swim the immense distance between the
contients and, therefore, lived while Australia and Antarctica were still joined together. Figure modified from
the Australia Department of Natural Resources and Scanlon (2005), Memoirs of the Queensland Museum.
Figure 4.1
Figure 4.2
Author: Bradley Deline
Author: The Queensland Museum
Source: Original Work
Source: The Queensland Museum
License: CC BY-SA 3.0
License: CC BY-NC-ND 3.0
How far have the snake fossils moved apart since they were originally deposited?
a. 1250 miles
b. 1700 miles
c. 2150 miles
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d. 2700 miles
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
6. Given that this portion of the Australian plate moves at a speed of 2.2 inches
per year, how old are the snake fossils?
a. 310 million years old
b. 217 million years old
c. 98 million years old
d. 62 million years old
e. 34 million years old
7. There are fossils such as Glossopteris and Lystrosaurus that are found in
rocks in South America and Africa that indicate they were part of Pangaea
approximately 200 million years ago. These same fossils can be found in
Australia, which indicates it, along with Antarctica, was also part of Pangaea at
that time. Based on your answer to question 6 which of the following statements
a out the rea u of an aea is
a. Australia and Antarctica separated before the break-up of Pangaea.
b. Australia and Antarctica separated during the break-up of Pangaea.
c. Australia and Antarctica separated after the break-up of Pangaea.
4.4 HOT SPOTS
Another line of evidence that can be used to track plate motion is the location
of hot spots. Hot spots are volcanically active areas on the Earth’s surface that
are caused by anomalously hot mantle rocks underneath. This heat is the result
of a mantle plume that rises from deep in the mantle toward the surface resulting
in melted rocks and volcanoes. These mantle plumes occur deep in the Earth such
that they are una e ted y the mo ement of the ontinents or the rust under the
o ean
ant e umes a ear to e stationary throu h time, ut as the te toni
plate moves over the hot spot a series of volcanoes are produced. This gives geologists a wonderful view of the movement of a plate through time with the distribution of volcanoes indicating the direction of motion and their ages revealing the
rate at which the plate was moving.
One of the most striking examples of a hot spot is underneath Hawaii. The
mantle plume generates heat that results in an active volcano on the surface of
the crust. Each eruption causes the volcano to grow until it eventually breaks the
surfa e of the o ean and forms an is and s the rust shifts the o ano o the hot
spot the volcano loses its heat and become inactive. The volcano then cools down,
contracts, erodes, sinks slowly beneath the ocean surface, and is carried by the tectonic plate as it moves through time. As each island moves away from the mantle
plume a new island will then be formed at the hot spot in a continual conveyor belt
of islands. Therefore, the scars of ancient islands near Hawaii give a wonderful
ie of the mo ement of the te toni
ate eneath the a i
ean
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INTRODUCTORY GEOLOGY
PL ATE TECTONICS
4.5 LAB EXERCISE
Materials
y e
a aii into the sear h ar of oo e arth and e amine the hain of
Hawaiian Islands. On a separate sheet of paper please draw yourself a map of the
is ands and a e the fo o in on your ma ma in sure to in ude the names ,
which will be used to answer the following questions.
Islands to include:
i
s and,
aui, auai,
ihoa
a. Put a North arrow on your map.
b. Label the ages of each of the islands determined by radiometric dating
of the lava.
i s and
a ti e ,
aui
mi ion, auai
mi ion, ihoa
mi ion years
a. Place a dot at the center of each island and measure on Google earth
the distance between the center of an island and its adjacent island in
entimeters for e am e measure the distan e et een the enter of
the i s and and aui
b. Look closely at each island in Google Earth and record their maximum
e e ation in entimeters emem er e e ation an e found y a in
your cursor over a point and reading the elevation on the lower right
of the image by the latitude and longitude. The elevation will be given
in meters, but can be converted to centimeters by multiplying by 100.
int ti tin the ima e of the is and i he to nd the hi hest oint
Part B - Hawaii
8. Consider the ages and positions of the islands listed above along with what
you know about plate tectonics and hotspots. In what general direction is the
a i
ate mo in
a. Northwest
9.
b. Southeast
c. Northeast
d. Southwest
o fast as the a i
ate mo in durin the ast
mi ion years et een
the formation of the i s and and aui in m year o a u ate this di ide the
distan e in entimeters et een the t o is ands y the di eren e in their a es
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INTRODUCTORY GEOLOGY
10.
PL ATE TECTONICS
o fast as the a i
ate mo in from
mi ion years a o to
mi ion years
ago between the formation of Kauai and Nihoa in cm/year? To calculate this divide
the distan e in entimeters et een the t o is ands y the di eren e in their a es
11. Examine the headings of the measurements that you took for the previous
t o uestions he headin s indi ate the dire tion the a i
ate is mo in
o er the hot s ot o does the dire tion of motion of the a i
ate durin
the ast
mi ion years di er from dire tion of mo ement et een
and
7.2 million years ago? The direction of plate movement in the last 1.1 million
years________.
a. shows no change
b. has become more southerly
c. has become more northerly
12. Zoom out and examine the dozens of sunken volcanoes out past Nihoa, named the
m eror eamounts s one of these o ani is ands on the a i
ate mo es
o the hots ot it e omes ina ti e, or e tin t, and the is and e ins to sin as it
and the surrounding tectonic plate cool down. The speed the islands are sinking
an e estimated y measurin the di eren e in e e ation et een t o is ands
and di idin y the di eren e in their a es this method assumes the is ands ere
a similar size when they were active). Calculate how fast the Hawaiian Islands are
sin in , y usin the a es and e e ations of aui and ihoa
13.
sin the s eed you a u ated in the re ious uestion and i norin ossi e
changes in sea level), when will the Big Island of Hawaii sink below the surface
of the ocean? Divide the current maximum elevation of the Big Island by the
rate you calculated in the previous question.
14.
o oom out to
mi es eye a titude and oo at the hain of a aiian
Islands again. Notice the chain continues for thousands of miles up to Aleutian
s ands et een as a and i eria
amine the northernmost sun en
o ano
in this hain
here as that o ano
located when it was still active, erupting, and above the surface of the ocean?
a. 50 49 16.99N 167 16 36.12E
b 52 31 48.72N 166 25 43.14W
c. 27 45 49.27N 177 10 08.75W
d. 19 28 15.23N 155 19 14.43W
4.6 PLATE MATERIALS
y no you an see many di erent ines of e iden e that the te toni
ates are
mo in there are many additiona ines of e iden e as e
o ui d a theory e
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INTRODUCTORY GEOLOGY
PL ATE TECTONICS
need an explanation or a mechanism that explains the patterns that we see. The theory of plate tectonics states that the outer ri id ayer of the earth the ithos here
is ro en into ie es a ed te toni
ates i ure
and that these ates mo e
inde endent y a o e the o in
asti i e ortion of the mant e sthenos here .
Figure 4.3 | Tectonic plates on Earth.
Author: USGS
Source: USGS
License: Public Domain
Tectonic plates are composed of the crust and the upper most mantle that
functions as a brittle solid. These plates can be composed of oceanic crust, continental crust or a mixture of both. The Oceanic Crust is thinner and normally
underlies the world’s oceans, while the Continental Crust is thicker and like its
name consists of the continents. The interaction of these tectonic plates is at the
root of many geologic events and features, such that we need to understand the
structure of the plates to better understand how they interact. The interaction of
these ates is ontro ed y the re ati e motion of t o ates mo in to ether,
apart, or sliding past) as well as the composition of the crustal portion of the plate
ontinenta or o ean rust
ontinenta rust has an o era om osition simi ar
to the igneous rock granite, which is a solid, silica-rich crystalline rock typically
onsistin of a mi ture of in fe ds ar , mi y hite fe ds ar , ear uart ,
and a
iotite minera s
eani rust is rimari y om osed of the i neous
rock gabbro, which is a solid, iron and magnesium-rich crystalline rock consisting
of a mi ture of a and dar ray minera s yro ene and fe ds ar
he di erPage | 72
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
ence in rock composition results in distinctive physical properties that you will
determine in the next set of questions.
4.7 LAB EXERCISE
Part C – Plate Densities
n im ortant ro erty of eo o i a
ates is their density mass o ume
emem er the asthenos here has uid i e ro erties, su h that te toni
ates
oat re ati e to their density his ro erty is a ed isostasy and is simi ar to
buoyancy in water. For example, if a cargo ship has a full load of goods it will
appear lower than if it were empty because the density of the ship is on average
higher. Therefore, the relative density of two plates can control how they interact
at a boundary and the types of geological features found along the border between
the t o ates easurin the density of ro s is fair y easy and an e done y rst
weighing the rocks and then calculating their volume. The latter is best done by a
method a ed uid dis a ement usin a raduated y inder
ater is added to
the cylinder and the level is recorded, a rock is then added to the cylinder and the
di eren e in ater e e s e ua s the o ume of the ro
ensity is then a u ated
as the mass di ided y the o ume i ure
The information needed to calculate density was collected for four rocks and can
e used to ans er the fo o in uestions in udin the ei ht in rams as well as
Figure 4.4 | Method to find the density of a rock. First the weight is measured on a digital scale and then
the fluid displacement method is used to determine the volume.
Author: Bradley Deline
Source: Original Work
License: CC BY-SA 3.0
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INTRODUCTORY GEOLOGY
PL ATE TECTONICS
the o ume of ater re orded y a raduated y inder in mi i iters efore and after
the rock was added. Note: each line on the graduated cylinder represents 10 ml.
hen measurin the o ume ease round to the nearest
mi i iter ine on the
graduated cylinder. Hint: Surface tension will often cause the water level to curve up
near the edges of the graduated cylinder creating a feature called a meniscus. To accurately measure the volume, use the lowest point the water looks to occupy.
Figure 4.5 | Figure to use to answer questions 15-19.The first row shows images of the four rocks. The
second and third rows show the volume (in milliliters) of material in the graduated cylinder before and after
the rock was added. The last row shows the mass (in grams) of the four rocks.
Author: Bradley Deline
Source: Original Work
License: CC BY-SA 3.0
The rock that most closely resembles the composition of continental crust
based on the description in the previous section is:
a. A
16.
b. B
c. C
d. D
ased on the hoi e you made for uestion , hat is the density of the ro s
that make up continental crust? Please give your answer in grams/milliliter.
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INTRODUCTORY GEOLOGY
PL ATE TECTONICS
17. The rock that most closely resembles the composition of oceanic crust based on
the description in the previous section is:
a. A
b. B
c. C
d. D
18. Based on the choice you made for question 17, what is the density of the rocks
that make up oceanic crust? Please give your answer in grams/milliliter.
19.
emem er, e ause of isostasy the denser ate i
e o er than the ess
dense plate. If oceanic and continental crust collided, based on their densities
the __________ crust would sink below the ________crust.
a. continental; oceanic
b. oceanic; continental
4.8 PLATE BOUNDARIES
e toni
ates an intera t in three di erent ays they an ome to ether,
they an u a art, or they an s ide y ea h other i ure
he other fa tor that an e im ortant is the om osition of the ates o eani or ontinenta
crust) that are interacting as was explored in the previous section. These three
types of motions along with the type of plates on each side of the boundary can
rodu e ast y di erent stru tures and eo o i e ents a e
Two plates that are moving apart from each other are called Divergent. Divergent boundaries are important because they are the way that continents split
apart and break into separate plates as well as where new ocean crust is formed.
If a divergent boundary forms within a continent that area stretches apart. This
results in the area becoming thinner creating a topographic low or a valley. This
extension is not a smooth process so the area is prone to earthquakes as well as
volcanic activity. Eventually, the crust gets so thin it will rupture forming a gap bet een the ates, hi h i e ed ith mo ten ro formin ne o eani rust
A thin and dense plate will be topographically low and will be covered in water
forming a long and narrow sea. As the plates persist in pulling apart new crust is
continually being formed at the plate boundary along an elevated crest known as a
mid-oceanic ridge.
Two plates that are moving together are called Convergent. Convergent
boundaries are important because they are the way distinctive plates can join
suture to ether to form ar er ates as e as here o ean rust is destroyed
The resulting structures we see at convergent boundaries depend on the types of
tectonic plates. If two thick and lower density continental plates converge we get
a large collision which results in mountains. This is a violent process resulting in
many earth ua es, deformation fo ds and fau ts of ro , and the u ift of mountains. The rocks are also under immense pressure and heat and will eventually
a e
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
become stuck together as a single plate. If a continental plate and an ocean plate
on er e ontinent o ean on er ent ate oundary there i e subduction,
where the oceanic plate sinks downward underneath the continental plate. This
will result in several features including a deep trench near the subducting plate,
abundant earthquakes, and the formation of magma which results in a line of volcanoes along the coast. Associated with this type of plate boundary is the Wadati-Benioff zone, a zone where earthquakes are produced; this zone ranges in
de th from sha o at the tren h to dee
m , indi atin that the o eani
plate is sinking into the mantle. If two oceanic plates converge it will also result in
subduction with similar features as were just discussed. The only exception will be
that the volcanoes will appear on an oceanic plate and will eventually form islands
along the tectonic boundary.
hen the t o ates s ide ast ea h other it is a ed a Transform boundary his ty e of oundary di ers from the re ious t o in that no ne
rust is
being formed and no old crust is being destroyed. Therefore, there won’t be as
many striking geologic features. Transform boundaries are often marked by abundant earthquakes that can be close to the surface as well as distinctive patterns of
ri ers that e ome o set as the and is mo in underneath them ransform
boundaries are also often associated with mid-oceanic ridges. If a the ridge has a
jagged or stair-stepped edge the pulling apart of the two tectonic plates will also
result in transform motion as you can see in Figure 4.6.
Figure 4.6 | Figure showing multiple plate boundaries and the features associated with them.
Author: José F. Vigil
Source: USGS
License: Public
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INTRODUCTORY GEOLOGY
PL ATE TECTONICS
Table 4.1. Characteristics of the different Plate Boundaries
Boundary
Type
Plate
Compositions
Earthquake Depth
Change in Crust
Identifying Features
ContinentContinent
Shallow
No change
Rift Valley and Volcanoes
Ocean-Ocean
Shallow
Formation of New Crust
Ocean Ridges
Shallow to Intermediate
Metamorphism of Crust
Mountains
Divergent
Convergent
ContinentContinent
ContinentOcean
Shallow to Deep
Melting of Crust
Trench and Coastal Volcanoes
Ocean-Ocean
Shallow To Deep
Melting of Crust
Trench and Volcanic Islands
ContinentContinent
Shallow
No change
Offset rivers
Ocean-Ocean
Shallow
No change
Often associated with Ocean ridges.
Transform
4.9 LAB EXERCISE
Part D – Origin of Magma
a ma is formed from the me tin of ro at oth on er ent and di er ent
oundaries o e er, the ro esses that o ur to me t the ro are uite di erent
hree di erent ro esses are in o ed in the me tin of ro s as e i e ore in
the following exercise. In Figure 4.7 you can see a graph depicting a variety of temperature and pressure conditions. The increasing temperature with pressure on
rocks as you go deeper within the earth through the crust and mantle lithosphere
is called the geothermal gradient
sho n in a
his radient
shows the actual temperature conditions that exist in the lithosphere.
Obviously, the addition or subtraction of heat or pressure can move
ro s o that radient and ause
potential change. The orange line
represents the temperature and
pressure required for a dry mantle
rock to start to melt and any point
to the right of this line is where
melting of lithospheric rock can
occur. The blue line represents the
temperature and pressure required Figure 4.7 | Melting diagram for mantle rock.
Author: Bradley Deline
for a lithospheric rock to melt if Source: Original Work
License: CC BY-SA 3.0
water is present.
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INTRODUCTORY GEOLOGY
20.
ordin to the eotherma radient, ro s uried
would normally be at what temperature?
t
m de th, ro s i
a. 1500
21.
b. 1250
radient, ro s at
de rees
e uried to a out
c. 20
b. Starting to melt
b. Starts to crystallize
i
e
m de th
at oint
c. Completely solid
ens hen the ithos here at oint
a. No change
e sius
d. 27
hat is the hysi a state of a dry mant e ro
hat ha
de rees e sius
d. 750
b. 12.5
a. Completely melted
m eneath the surfa e
c. 1000
de rees e sius, ro s i
a. 8
23.
e heated to a out
ordin to the eotherma
buried how deep?
t
22.
PL ATE TECTONICS
is heated to
c. Starts to melt
24. t hat de th i the dry mant e ro at oint
e in to me t if it is u ifted
closer to Earth’s surface and its temperature remains the same?
a. 35 km
hat ou d ha
a. No change
b. 25 km
c. 18 km
en to the mant e ro
at oint
b. Starts to crystallize
d. 12 km
if ater is added to it
c. Starts to melt
Part E – Boundaries
Earthquakes are great indicators of plate boundaries and are associated with
a three oundary ty es ne ty e of oundary is uni ue in ha in a adati enio one ns er the fo o in uestions usin i ure
Page | 78
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
Figure 4.8 | Distribution and depth of Earthquakes.
Author: USGS
Source: USGS
License: Public Domain
26.
hi h of the fo o in
a. 10°S, 110°W
27. he
adati
a es re resent a
b. 0°, 0°
enio
adati
c. 15°S, 180°
enio
one
d. 30°N, 75°E
one is asso iated ith hi h ty e of
a. Divergent
ate oundary
b. Convergent (Continent-Continent)
c. Convergent (Continent-Ocean or Ocean-Ocean) d. Transform
y e
into the sear h ar in oo e arth and
zoom out to an eye altitude of 10 miles. Quail Lake is a dammed river that is sitting
directly over top of the San Andres Fault, which is a well-known transform boundary ith the orth meri an ate on the northern side and the a i
ate on
the southern side his oundary is runnin ast est in this area and you may e
able to see the boundary better by zooming out.
28.
amine the ath of the ri er that feeds into and o s out of uai a e
dire tion is the orth meri an ate mo in in om arison to the a i
at this location?
a. East
b. West
Page | 79
hat
ate
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
29. Given that San Francisco is located on the North American Plate and Los
n es is o ated on the a i
ate, are these t o ities ettin oser to ether
or farther apart over time?
a. Closer
b. Farther
Google Earth: Identifying Plate Boundaries
e read the se tion on
ate oundaries efore ans erin the fo o in
30. y e
of tectonic plates are present?
a. Ocean- Ocean
31.
hat ty e of
into the oo e arth ear h ar
b. Ocean- Continent
ate te toni
a. Transform
c. Continent- Continent
c. Divergent
32. y e
into the oo e arth ear h ar
of process is going on at this location?
33.
b. Continental rifting
hat features ou d you e
e t to o ur at this ty e of oundary
b. Volcanoes and a valley
c. Mountains and landslides
d. Earthquakes and offset rivers
34. y e
type of tectonic plates are present?
hat ty e of
a. Transform
oo e arth ear h ar
hat
c. Continent- Continent
oundary is resent
b. Convergent
36. y e
ty e of te toni
ates are resent
of the relevant features.
a. Ocean- Ocean
into the
b. Ocean- Continent
ate te toni
hat ty e
c. Subduction
a. Earthquakes and a trench
a. Ocean- Ocean
hat ty e
oundary is resent
b. Convergent
a. Seafloor spreading
uestions
c. Divergent
into the oo e arth ear h ar
hat
a e sure to oom out to et a ood ie
b. Ocean- Continent
Page | 80
c. Continent- Continent
INTRODUCTORY GEOLOGY
37.
PL ATE TECTONICS
hat features ou d you e
e t to o ur at this ty e of oundary
a. Volcanos, earthquakes and a trench
b. Volcanoes and a linear valley
c. Mountains and landslides
d. Earthquakes and offset rivers
38. y e
into the oo e arth ear h ar
hat
type of tectonic plates are present? Hint- make sure to re-read the section on
plate boundaries before answering!
a. Ocean- Ocean
39.
hat ty e of
a. Transform
b. Ocean- Continent
ate te toni
c. Continent- Continent
oundary is at this e a t o ation
b. Convergent
c. Divergent
40. This plate boundary isn’t as simple as the previous examples, meaning another
near y ate oundary dire t y in uen es it oom out and e amine the area,
what other type of boundary is nearby?
a. Transform
b. Convergent
c. Divergent
4.10 PLATE TECTONIC MECHANISMS
The question still remains, why do tectonic plates move? The answer comes
down to gravity and mantle convection. You have already studied in chapter two
ho the mant e o s throu h time reatin on e tion urrents hese on e tion
urrents o underneath the ates and throu h fri tion u them a on at the
surface as well as when they are subducted which is a force called slab suction.
e ated to this for e is slab pull, which is a gravitational force pulling the cold
subducting plate down into the mantle at a subduction zone. In addition, there is
a force from potential energy at ocean ridges called ridge push. This is a gravitational force pushing down on the elevated ridge and because of the plates curvature it results in a horizontal force pushing the plate along the earth’s surface.
These forces all occur deep inside the Earth and operate on very large geographic
s a es ma in them di u t to measure here are se era om etin mode s for
the mechanisms behind plate motion, such that there are still some areas of debate
surrounding the mechanics of plate tectonics which is why Plate Tectonics is a
s ienti theory o umentin an e ent is mu h easier and more strai htfor ard
than explaining why it occurred.
Page | 81
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
4.11 LAB EXERCISE
Part F – Mechanisms
41. Go back to the location in Google Earth that you examined for question 36
hi h of the three ro osed ate te toni
mechanisms would NOT occur at this location?
a. Slab pull
b. Ridge push
c. Slab suction
Reference
a on,
uamata
useum
ustra ia s o dest no n sna es Patagoniophis, Alamitophis and c.f. Madtsoia
adtsoiidae from the o ene of ueens and
emoirs of the ueens and
Page | 82
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
4.11 STUDENT RESPONSES
The following is a summary of the questions in this lab for ease in submitting
answers online.
1.
ra i
2.
n oa
atitude and on itude
atitude and on itude
3.
easure in entimeters the distan e
a en th et een the t o oints you
recorded in the previous question. Given that this portion of Pangaea broke
apart 200,000,000 years ago, calculate how fast South America and Africa are
se aratin in m year
int
eed
istan e ime
4.
hen i the ne t su er ontinent form
amine the estern oast of outh
meri a, the astern oast of sia, and the a i
ean f outh meri a and
Africa are separating and the Atlantic Ocean is growing, then the opposite must
e o urrin on the other side of the earth the meri as are ettin
oser to
sia and the a i
ean is shrin in
o far a art are orth meri a and
ain and sia in m measure the distan e a ross the a i at
de rees
north latitude- basically measure between Northern California and North
Korea)? Take that distance and divide it by the speed you calculated in question
3 to estimate when the next supercontinent will form. Show your work!
How far have the snake fossils moved apart since they were originally deposited?
a. 1250 miles
b. 1700 miles
c. 2150 miles
Page | 83
d. 2700 miles
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
6. Given that this portion of the Australian plate moves at a speed of 2.2 inches
per year, how old are the snake fossils?
a. 310 million years old
b. 217 million years old
c. 98 million years old
d. 62 million years old
e. 34 million years old
7. There are fossils such as Glossopteris and Lystrosaurus that are found in
rocks in South America and Africa that indicate they were part of Pangaea
approximately 200 million years ago. These same fossils can be found in
Australia, which indicates it, along with Antarctica, was also part of Pangaea at
that time. Based on your answer to question 6 which of the following statements
a out the rea u of an aea is
a. Australia and Antarctica separated before the break-up of Pangaea.
b. Australia and Antarctica separated during the break-up of Pangaea.
c. Australia and Antarctica separated after the break-up of Pangaea.
8. Consider the ages and positions of the islands listed above along with what
you know about plate tectonics and hotspots. In what general direction is the
a i
ate mo in
a. Northwest
b. Southeast
c. Northeast
d. Southwest
9.
o fast as the a i
ate mo in durin the ast
mi ion years et een
the formation of the i s and and aui in m year o a u ate this di ide the
distan e in entimeters et een the t o is ands y the di eren e in their a es
10.
o fast as the a i
ate mo in from
mi ion years a o to
mi ion
years ago between the formation of Kauai and Nihoa in cm/year? To calculate
this di ide the distan e in entimeters et een the t o is ands y the
di eren e in their a es
Page | 84
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
11. Examine the headings of the measurements that you took for the previous
t o uestions he headin s indi ate the dire tion the a i
ate is mo in
o er the hot s ot o does the dire tion of motion of the a i
ate durin
the ast
mi ion years di er from dire tion of mo ement et een
and
7.2 million years ago? The direction of plate movement in the last 1.1 million
years________.
a. shows no change
b. has become more southerly
c. has become more northerly
12. Zoom out and examine the dozens of sunken volcanoes out past Nihoa, named the
m eror eamounts s one of these o ani is ands on the a i
ate mo es
o the hots ot it e omes ina ti e, or e tin t, and the is and e ins to sin as it
and the surrounding tectonic plate cool down. The speed the islands are sinking
an e estimated y measurin the di eren e in e e ation et een t o is ands
and di idin y the di eren e in their a es this method assumes the is ands ere
a similar size when they were active). Calculate how fast the Hawaiian Islands are
sin in , y usin the a es and e e ations of aui and ihoa
13.
sin the s eed you a u ated in the re ious uestion and i norin ossi e
changes in sea level), when will the Big Island of Hawaii sink below the surface
of the ocean? Divide the current maximum elevation of the Big Island by the
rate you calculated in the previous question.
14.
o oom out to
mi es eye a titude and oo at the hain of a aiian
Islands again. Notice the chain continues for thousands of miles up to Aleutian
s ands et een as a and i eria
amine the northernmost sun en
o ano
in this hain
here as that o ano
located when it was still active, erupting, and above the surface of the ocean?
a. 50 49 16.99N 167 16 36.12E
b 52 31 48.72N 166 25 43.14W
c. 27 45 49.27N 177 10 08.75W
d. 19 28 15.23N 155 19 14.43W
The rock that most closely resembles the composition of continental crust
based on the description in the previous section is:
a. A
b. B
c. C
a e
d. D
INTRODUCTORY GEOLOGY
16.
PL ATE TECTONICS
ased on the hoi e you made for uestion , hat is the density of the ro s
that make up continental crust? Please give your answer in grams/milliliter.
17. The rock that most closely resembles the composition of oceanic crust based on
the description in the previous section is:
a. A
b. B
c. C
d. D
18. Based on the choice you made for question 17, what is the density of the rocks
that make up oceanic crust? Please give your answer in grams/milliliter.
19.
emem er, e ause of isostasy the denser ate i
e o er than the ess
dense plate. If oceanic and continental crust collided, based on their densities
the __________ crust would sink below the ________crust.
a. continental; oceanic
20.
ordin to the eotherma radient, ro s uried
would normally be at what temperature?
t
m de th, ro s i
a. 1500
21.
b. 1250
radient, ro s at
de rees
e uried to a out
c. 20
b. Starting to melt
a. No change
b. Starts to crystallize
Page | 86
at oint
c. Completely solid
ens hen the ithos here at oint
e sius
i
m de th
d. 27
hat is the hysi a state of a dry mant e ro
hat ha
de rees e sius
d. 750
b. 12.5
a. Completely melted
m eneath the surfa e
c. 1000
de rees e sius, ro s i
a. 8
23.
e heated to a out
ordin to the eotherma
buried how deep?
t
22.
b. oceanic; continental
is heated to
c. Starts to melt
e
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
24. t hat de th i the dry mant e ro at oint
e in to me t if it is u ifted
closer to Earth’s surface and its temperature remains the same?
a. 35 km
b. 25 km
hat ou d ha
a. No change
26.
en to the mant e ro
a. 10°S, 110°W
adati
enio
if ater is added to it
c. Starts to melt
a es re resent a
b. 0°, 0°
d. 12 km
at oint
b. Starts to crystallize
hi h of the fo o in
27. he
c. 18 km
adati
c. 15°S, 180°
enio
one
d. 30°N, 75°E
one is asso iated ith hi h ty e of
a. Divergent
ate oundary
b. Convergent (Continent-Continent)
c. Convergent (Continent-Ocean or Ocean-Ocean) d. Transform
28.
amine the ath of the ri er that feeds into and o s out of uai a e
dire tion is the orth meri an ate mo in in om arison to the a i
at this location?
a. East
hat
ate
b. West
29. Given that San Francisco is located on the North American Plate and Los
n es is o ated on the a i
ate, are these t o ities ettin oser to ether
or farther apart over time?
a. Closer
b. Farther
30. y e
of tectonic plates are present?
a. Ocean- Ocean
31.
hat ty e of
into the oo e arth ear h ar
b. Ocean- Continent
ate te toni
a. Transform
c. Continent- Continent
oundary is resent
b. Convergent
c. Divergent
32. y e
into the oo e arth ear h ar
of process is going on at this location?
a. Seafloor spreading
hat ty e
b. Continental rifting
Page | 87
c. Subduction
hat ty e
INTRODUCTORY GEOLOGY
33.
PL ATE TECTONICS
hat features ou d you e
e t to o ur at this ty e of oundary
a. Earthquakes and a trench
b. Volcanoes and a valley
c. Mountains and landslides
d. Earthquakes and offset rivers
34. y e
type of tectonic plates are present?
a. Ocean- Ocean
hat ty e of
b. Ocean- Continent
ate te toni
a. Transform
b. Convergent
a. Ocean- Ocean
oo e arth ear h ar
hat
c. Continent- Continent
oundary is resent
36. y e
ty e of te toni
ates are resent
of the relevant features.
37.
into the
into the oo e arth ear h ar
hat
a e sure to oom out to et a ood ie
b. Ocean- Continent
hat features ou d you e
c. Divergent
c. Continent- Continent
e t to o ur at this ty e of oundary
a. Volcanos, earthquakes and a trench
b. Volcanoes and a linear valley
c. Mountains and landslides
d. Earthquakes and offset rivers
38. y e
into the oo e arth ear h ar
hat
type of tectonic plates are present? Hint- make sure to re-read the section on
plate boundaries before answering!
a. Ocean- Ocean
39.
hat ty e of
a. Transform
b. Ocean- Continent
ate te toni
c. Continent- Continent
oundary is at this e a t o ation
b. Convergent
c. Divergent
40. This plate boundary isn’t as simple as the previous examples, meaning another
near y ate oundary dire t y in uen es it oom out and e amine the area,
what other type of boundary is nearby?
a. Transform
b. Convergent
Page | 88
c. Divergent
INTRODUCTORY GEOLOGY
PL ATE TECTONICS
41. Go back to the location in Google Earth that you examined for question 36
hi h of the three ro osed ate te toni
mechanisms would NOT occur at this location?
a. Slab pull
b. Ridge push
Page | 89
c. Slab suction